Piecing together the Chiseldon cauldrons puzzle

Alexandra Baldwin, British Museum

As is often the case, the painstaking process of excavating the cauldron I’m working on has been more complex and time consuming than we initially thought.

The majority of the cauldron was lifted from its findspot in a block of soil supported by plaster bandages. Hundreds of smaller fragments were also removed from around the object during excavation. The fragmentary state of this cauldron is partially due to the fact that it was buried upside down, and over time the weight and the pressure of the overlying soil crushed and distorted it.

I began by carefully cutting away thin strips of plaster to reveal the top of the block and clear soil from the metal. With heavy clay soil, which is more solid than the objects, this has to be done with great care using scalpels and leaf trowels to remove soil dampened with water and alcohol.

Working down in layers, the sheet metal is uncovered, and the true condition of the object revealed. It is highly fragmentary and even undisturbed areas are in pieces.

Fragments loose in the soil have to be rejoined back onto larger sections immediately otherwise their location will be lost. This is done using thin tabs of nylon gossamer, a thin random weave of synthetic fibres, adhered over the join.

Removing the plaster support and soil from around the object makes it very unstable and because of this you are unable to see the entire object at once; the metal is so thin and fragile that it is unable to support its own weight.

I have now laid out the fragments from the excavation on a large table and have been looking for joins between them, and also between the fragments and metal contained in the soil block. Although I have found a number of joins there have been disappointingly few.

Very quickly it became apparent that there was something strange about this cauldron – there seemed to be too much copper alloy – several folded layers in the block as well as large sheet fragments.

From knowledge of other cauldrons we can tell that they are made in sections riveted together; the iron rim supporting the handles, then below this, two sections of copper alloy bowl. As I began to reveal more it appeared that there were two bases on top of each other – was this two cauldrons one inside another? Or were we looking at areas of a separate cauldron either displaced during burial or placed into the pit in fragments?

As each layer is revealed the position of the fragments is carefully recorded. Stephen Crummy, one of the Museum’s illustrators, has been using 3D laser scanning and photogrametery to map the block.

The next stage will be to try and decipher and interpret the remains. Then, after supporting and stabilising them, we will remove sections of the metal, effectively disassembling the object from around the soil.

The Chiseldon cauldrons research project is supported by the Leverhulme Trust